<template>
  <el-breadcrumb class="app-breadcrumb" separator="/">
    <transition-group name="breadcrumb">
      <el-breadcrumb-item v-for="(item, index) in levelList" :key="item.path">
        <span v-if="item.redirect === 'noRedirect' || index == levelList.length - 1" class="no-redirect">{{ item.meta.title }}</span>
        <a v-else @click.prevent="handleLink(item)">{{ item.meta.title }}</a>
      </el-breadcrumb-item>
    </transition-group>
  </el-breadcrumb>
</template>

<script>
  export default {
    data() {
      return {
        levelList: null
      }
    },
    watch: {
      $route(route) {
        // if you go to the redirect page, do not update the breadcrumbs
        if (route.path.startsWith('/redirect/')) {
          return
        }
        this.getBreadcrumb()
      }
    },
    created() {
      this.getBreadcrumb()
    },
    methods: {
      getBreadcrumb() {
        // only show routes with meta.title
        let matched = []
        const router = this.$route
        const pathNum = this.findPathNum(router.path)
        // multi-level menu
        if (pathNum > 2) {
          const reg = /\/\w+/gi
          const pathList = router.path.match(reg).map((item, index) => {
            if (index !== 0) item = item.slice(1)
            return item
          })
          this.getMatched(pathList, this.$store.getters.defaultRoutes, matched)
        } else {
          matched = router.matched.filter(item => item.meta && item.meta.title)
        }
        // 判断是否为首页
        if (!this.isDashboard(matched[0])) {
          matched = [{ path: "/index", meta: { title: "首页" } }].concat(matched)
        }
        this.levelList = matched.filter(item => item.meta && item.meta.title && item.meta.breadcrumb !== false)
      },
      findPathNum(str, char = "/") {
        let index = str.indexOf(char)
        let num = 0
        while (index !== -1) {
          num++
          index = str.indexOf(char, index + 1)
        }
        return num
      },
      getMatched(pathList, routeList, matched) {
        let data = routeList.find(item => item.path == pathList[0] || (item.name += '').toLowerCase() == pathList[0])
        if (data) {
          matched.push(data)
          if (data.children && pathList.length) {
            pathList.shift()
            this.getMatched(pathList, data.children, matched)
          }
        }
      },
      isDashboard(route) {
        const name = route && route.name
        if (!name) {
          return false
        }
        return name.trim() === 'Index'
      },
      handleLink(item) {
        const { redirect, path } = item
        if (redirect) {
          this.$router.push(redirect)
          return
        }
        this.$router.push(path)
      }
    }
  }
</script>

<style lang="scss" scoped>
  .app-breadcrumb.el-breadcrumb {
    display: inline-block;
    font-size: 14px;
    line-height: 50px;
    margin-left: 8px;
  .no-redirect {
    color: #97a8be;
    cursor: text;
  }
  }
</style>
